During the production of hydrocarbons from a wellbore and/or during the placement of one or more completion strings (e.g., strings of casing) in the wellbore, one or more properties of the wellbore and surrounding subterranean formations may need to be measured. For instance, electromagnetic (EM) sensors are often deployed in completion strings to make azimuth measurements, which can be used to detect the direction of an approaching water flood.
One challenge with deploying EM sensors is that the transmitters and receivers associated with the EM sensors should be positioned as close as possible to the surrounding subterranean formation while being isolated and as far away as possible from the completion string. To accomplish this, various designs with EM sensors on centralizers and swell packers have been proposed, and the challenge with these designs is the fact that the clearance between the EM sensors and the formation while being run into the wellbore is very limited. As a result, the EM sensors often run the risk of abrasion or being crushed while conveyed to a target location within the wellbore.
Once reaching the target location, deploying EM sensors on a completion string is traditionally done using swellable packers or packer elements. However, this requires machined packers for every location where a sensor is required, and therefore can be cost prohibitive for a system where several EM sensors are to be used. Moreover, sensors deployed through the use of swellable packers or packer elements may also be damaged due to abrasion and/or crush forces since such sensors need to be located on the outside of the swell packer for them to contact the surrounding formation once the packer swells. On the other hand, deploying EM sensors positioned on spring centralizers may cause the EM sensors to drag against the formation while being run downhole, and thereby risking drag/abrasion damage to the EM sensors.